1. Field of the Invention
The present invention is directed generally to truck bodies having top hinged pivoting rear gates including those designed specifically for refuse hauling. More particularly, the invention concerns an improved positive tailgate latching mechanism for rearward compacting, rear discharge refuse hauling trucks which relieves hinge stress, prevents ride up and automates latching and unlatching of the tailgate. Applicable to both front-loading or side-loading rear discharge vehicles, the invention allows automated remote operation of the tailgate.
2. Description of the Related Art
Trucks performing specialized tasks as for loading, hauling and discharging various types of loads such as refuse are common. These vehicles include a basic truck chassis fitted with a distinctly configured separate body that is typically designed, built and installed on the chassis by a second manufacturer. The truck body is, then, specifically designed to accommodate desired specialty tasks. A refuse truck, for example, includes, in addition to a storage container, systems for receiving, compacting and discharging refuse materials complete with all the associated operating mechanisms.
One successful design of refuse hauling truck bodies is known as a "front loader" and includes a refuse hauling reservoir accessible for loading through a hopper cover in the top front portion of the vehicle body. A rather large, substantially vertically disposed tailgate forms the closure for the rear of an elongated refuse holding reservoir aft of or including the receiving hopper. This system includes an hydraulic compacting mechanism which is used to repeatedly compact the refuse rearward with great force after each loading. In this manner, refuse eventually fills the available or usable reservoir volume extending from the front end back toward the rear of the body until no more material can be compacted.
The tailgate closing the rear of the container is designed to be raised vertically and swung outward to open. It is hingedly connected at the top rear of the truck body and is equipped with a pair of side mounted cylinders to displace it vertically and pivot it about the hinges. The bottom of the tailgate, when lowered or in the closed position, is typically secured by dog-ear type drop-in latches in the lower rear structural supports in the back of the refuse truck body. The tailgate may be opened by raising it slightly using the cylinders to clear the drop-in latches and thereafter pivoting upward to completely expose the rear of the reservoir. The collection and compaction systems are operated with the tailgate down and latched to the truck body. Ejection of the accumulated contents is accomplished when the tailgate is unlatched and swung upward and out of the way and the entire rear of the refuse holding reservoir is open so that the collected material may just be pushed rearward and discharged from the body of the truck beneath the raised tailgate.
The compacting mechanism is operated by an hydraulic cylinder which mounts behind the cab and reciprocally moves a large blade member against the refuse in the manner of a snowplow. The packing blade also serves as the ejector blade. As the refuse is compacted aft on an horizontal plane against the tailgate, it serves not only as a closure means but also as an end wall which must be capable of withstanding the full force of the compacting operation and compacted refuse. The top hinge mechanisms and the bottom latches are the only points of support for the tailgate. The compacting and holding of compacted refuse, then, necessarily produces a great deal of corresponding strain in the hinge mechanism and in the bottom latches. As a result of the forces against it, prior tailgates also tend to ride up and may even unlatch. The top pivot members of the hinge mechanism must be extremely rugged in construction and, even so, the extreme conditions also produce undue wear on moving parts.
Accordingly, it is a primary object of the present invention to provide an integral automatic latching mechanism which overcomes the above-enumerated problems.
Another object of the invention it to provide an integral automatic latching mechanism that reduces the stress on the top pivot members produced by refuse compacted within the vehicle refuse container volume and precludes the tendency of the tailgate to ride up during compaction by the provision of latches to secure the sides of the tailgate in addition to the top and bottom when the tailgate is in the lowered position.
A further object of the invention is to provide pairs of double hook drop-in latches to secure the sides of the tailgate such that the horizontal force against the tailgate is carried by the latches.
Another object of the present invention is to provide positive vertical stops to prevent the closed tailgate from riding up.
A still further object of the invention is to enable the automatic positive tailgate latching mechanism to be operated entirely by a pair of vertically disposed hydraulic cylinders, one on each side of the rear of the vehicle.
These and other objects will become apparent in view of the description below taken together with the several drawings and the claims appended hereto.